By Pat Toomey

In the summertime, kids are typically found outside. My two older children, Bridget and Patrick, ride bikes and swim. Other kids practically live at the baseball diamond or basketball court. It's part of what makes summer special.

But for 12-year old Sarah Murnaghan of Delaware County, this summer is extra special: She is just beginning to do all the fun things so many other kids take for granted.

Among girls her age, Sarah stands apart. Not because she recently had a breathing tube removed from her throat, and not because she was the grand marshal at the Marple Newtown Fourth of July parade.

Sarah is different because she fought for her life and won, and her victory will save other kids' lives too. Sarah, from Newtown Square, has been battling cystic fibrosis for some time now. As her family has told me, cystic fibrosis clogs the lungs and makes it very hard to breathe. Resulting infections further damage her organs.

Last spring, at the age of 10, Sarah was close to death.

Her condition had grown desperate; her doctors at the Children's Hospital of Philadelphia predicted that she had only weeks to live, unless she received a successful lung transplantation.

Medical need is usually a leading factor for prioritization on the lung transplant waiting list. By that criterion, Sarah would have likely ranked near the top of the donor list for a new lung. But a federal policy prevented children under age 12 from being considered for a mature lung until all adult candidates in the region were ruled out. This made the likelihood of Sarah receiving a life-saving transplant remote, due to the short supply of child donors.

Sarah's family took the fight to social media, to the Department of Health and Human Services, and to the Organ Procurement and Transplantation Network. They asked that children under 12 be considered for adult lung transplants - using the same criteria for adult consideration - if doctors substantiated that an adult transplant would be viable.

As Sarah herself said, "I'm not going for easy, I'm going for possible."

After speaking with Sarah's mother, Janet, I took Sarah's cause to then-Secretary of Health and Human Services Kathleen Sebelius. I asked the secretary to use her authority to make medical need and suitability, rather than age, the primary criteria in determining how organ donations are prioritized. I asked her to free the transplantation network to help children who needed lung transplants.

My request was not honored.

At one point, Sarah's family filed legal action to prevent Sebelius from enforcing the policy that prohibited children from consideration. It looked grim for Sarah. But then, a federal judge issued a temporary restraining order, which allowed Sarah to receive the life-saving transplant she needed. It was touch and go for a while. Sarah had trouble with the first set of lungs. A second set was a perfect fit.

Sarah Murnaghan is now breathing on her own and riding her bike with her brothers and sister. She's proof that adult organs fitted to size can work in children.

But Sarah's victory was not yet complete. Her case was an exception and the rule prohibiting suitable children from receiving adult lungs was still in place. This summer, the transplant network permanently revised the under-12 policy. The new regulation, in place on a temporary basis since June 2013, allows candidates age 11 or younger to petition a national lung review board to qualify as an adolescent, which would make them eligible for an adult lung.

I was honored to take up Sarah's cause more than a year ago. Along with many other Pennsylvanians, I was thrilled when the Organ Procurement and Transplantation Network amended its rule - permanently - so that children like Sarah are not blocked from potentially life-saving transplants just because of their age.

Sarah is a tough little girl. She just turned 12 this month. She has been through a lot, but she has accomplished even more. Along with her family, Sarah fought for her life and for fair treatment for kids needing transplants. She won both battles. Now, she is riding her bike, playing outside, and will soon go back to school with her friends.

Pat Toomey is a Republican U.S. senator from Pennsylvania.